This invention relates to the technical field of an image recording apparatus that forms a latent image on light-sensitive materials (photographic papers) by scan exposure.
Heretofore, the image recorded on photographic films such as negatives and reversals (which are hereunder referred to simply as "films") has been commonly printed on light-sensitive materials by means of direct (analog) exposure, in which projected light from the film is allowed to be incident on the light-sensitive material to achieve its areal exposure.
A new technology has recently been introduced and this is a printer that relies upon digital exposure. Briefly, the image recorded on a film is read photoelectrically, converted to a digital signal and subjected to various image processing operations to produce image data for recording purposes; recording light that has been modulated in accordance with the image data is used to scan and expose a light-sensitive material to record a latent image, which is subsequently developed and output as a print (photograph). The printer operating on this principle has been commercialized as a digital photoprinter.
In the digital photoprinter, the image on a film is read photoelectrically and gradation correction and other operations are performed by subsequent image (signal) processing to determine exposing conditions. Hence, the digital photoprinter has many capabilities in image processing such as editing of printed images by, for example, assembling a plurality of images or splitting a single image into plural images, as well as color/density adjustment and edge enhancement; as a result, prints can be output as needed by specific uses. In addition, the data on a printed image can be supplied into a computer or the like and stored in recording media such as a floppy disk or a hard disk.
A further advantage of the digital photoprinter is that compared to the prints produced by the conventional method of direct exposure, those which are output by the digital photoprinter have better image quality in such aspects as resolution and color/density reproduction.
Having these features, the digital photoprinter is basically composed of an input machine having a scanner (image reader) and an image processor and an output machine having both an exposing device (image recording device) and a developing device.
In the scanner, projected light carrying the image recorded on a film is read photoelectrically with an image sensor such as a CCD sensor and the captured image is sent to the image processor as data for the image on the film (i.e., the image data signal). In the image processor, the image data from the scanner are subjected to specified image processing operations and the resulting output image data for image recording (i.e., exposing conditions) are sent to the exposing device.
In the exposing device, if it is of a type that relies upon exposure by scanning with an optical beam, the latter is modulated in accordance with the received image data and deflected in a main scanning direction as the light-sensitive material is transported in an auxiliary scanning direction perpendicular to the main scanning direction, whereby a latent image is formed as the result of scan exposure of the light-sensitive material with the optical beam and a back print is also recorded. In the developing device, the exposed light-sensitive material is subjected to development and other specified processing operations so as to output a print which reproduces the image that has been recorded on the film.
In the exposing device, whether it is in the digital photoprinter or an ordinary photoprinter that relies upon "direct" exposure, a virgin light-sensitive material is in the form of a magazine, i.e., a roll contained in a lightproof case. The light-sensitive material is withdrawn out of the magazine in the exposing device and further transported for exposure and other necessary steps.
In the ordinary photoprinter, the light-sensitive material being transported is not cut but remains a web as it is subjected to exposure, back print recording, development, rinse, drying and other necessary steps and only after these steps are complete, the light-sensitive material is cut to individual prints of a specified length.
This process requires that frame information (frame punches) for delineating individual frames (or prints) be formed before or during the exposure of the light-sensitive material. However, the portion of the light-sensitive material where the frame information is formed is simply a waste of space. In addition, frame information have to be formed by special means having a punch, a sensor or the like.
In the exposing device of a digital exposure type, the light-sensitive material must be transported for scanning in high precision and without stops in order to record images of high quality that are free from unevenness and other defects. In order to meet this need, the exposing device in the digital photoprinter is adapted to make a slack (loop) out of the light-sensitive material both upstream and downstream of the exposing position but this only increases the complexity of the transport zone for the light-sensitive material and the mechanism for its control.
Under the circumstances, an exposing device is desired that can be incorporated in a digital photoprinter and which is capable of exposing a light-sensitive material after it is cut to sheets corresponding to individual prints to be finally produced. In fact, this need has been satisfied commercially with an analog photoprinter.
In order to produce prints with appropriate image reproduction, the light-sensitive material has to be supplied to the recording (exposing) position in a skewless appropriate posture. As already mentioned, digital exposure involves two-dimensional scanning of the light-sensitive material with optical beams or the like that are deflected in the main scanning direction which is perpendicular to the auxiliary scanning direction in which the light-sensitive material is being transported. Therefore, if the light-sensitive material skews when it is supplied to the recording position, the main scanning line defined by the optical beams or the like also skews with respect to the light-sensitive material, reproducing a curved image on the final print.
To avoid this problem, the conventional image recording apparatus has a paper position regulating guide provided upstream of the auxiliary scanning transport means for regulating the direction of transport of the light-sensitive material as it is held in contact with an edge portion of the light-sensitive material. Since the light-sensitive material is transported as its end portion is held in contact with the paper position regulating guide, the light-sensitive material is directed by means of the guide so that the posture of the light-sensitive material is rendered appropriate before it is supplied to the recording position.
In this method of regulating the position of the light-sensitive material using the paper position regulating guide, any skew in the posture of the light-sensitive material is corrected by forcing it into contact with the guide. Therefore, if, in the case where the guide is placed just upstream of the exposing section, the light-sensitive material has to be moved by a substantial amount before it contacts the guide, the quality of the image on the final print may occasionally be affected adversely. Conversely, if the guide is placed remote from the recording position, the light-sensitive material may skew again while it is transported from the guide to the recording position.
Thus, it has been desired to develop an image recording apparatus that is capable of performing appropriate imagewise exposure in a consistent manner by supplying a light-sensitive material to the recording position in a skewless appropriate posture.